Peripheral Islands Research Articles

Central Retinal Artery Occlusion: Visual Outcome

To investigate systematically the natural history of visual outcome in central retinal artery occlusion (CRAO). Cohort study. At entry, 244 consecutive patients (260 eyes) with CRAO (seen consecutively from 1973 to 2000) had a detailed ocular and medical history and ocular evaluation. CRAO eyes were classified into four categories: non-arteritic (NA) CRAO (171 eyes), NA-CRAO with cilioretinal artery sparing (35), transient NA-CRAO (41), and arteritic CRAO (13). Within 7 days of onset of CRAO, initial visual acuity differed among the four CRAO types (P < .0001). In eyes with vision of counting fingers or worse, it improved in 82% of eyes with transient NA-CRAO, 67% of eyes with NA-CRAO with cilioretinal artery sparing, and 22% of eyes with NA-CRAO. Visual acuity improved primarily within the first 7 days (P < .0001). In the central 30-degree visual field, central scotoma was most common. Central visual field improved in 39% with transient NA-CRAO, 25% with NA-CRAO with cilioretinal artery sparing, and 21% with NA-CRAO. Peripheral visual field was normal in 62.9% of eyes with transient NA-CRAO and 22.1% in those with NA-CRAO. In 51.9% of eyes with NA-CRAO, the only remaining visual field was a peripheral island. Peripheral fields improved in NA-CRAO (39%) and in transient NA-CRAO (39%). Classification of CRAO is crucial for understanding differences in visual outcome. Marked improvement in visual acuity and visual field can occur without treatment and is determined by several factors. Visual field information is essential to evaluate visual disability in CRAO.

Comparative landscape genetics and the adaptive radiation of Darwin's finches: the role of peripheral isolation

We use genetic divergence at 16 microsatellite loci to investigate how geographical features of the Galápagos landscape structure island populations of Darwin's finches. We compare the three most genetically divergent groups of Darwin's finches comprising morphologically and ecologically similar allopatric populations: the cactus finches (Geospiza scandens and Geospiza conirostris), the sharp-beaked ground finches (Geospiza difficilis) and the warbler finches (Certhidea olivacea and Certhidea fusca). Evidence of reduced genetic diversity due to drift was limited to warbler finches on small, peripheral islands. Evidence of low levels of recent interisland migration was widespread throughout all three groups. The hypothesis of distance-limited dispersal received the strongest support in cactus and sharp-beaked ground finches as evidenced by patterns of isolation by distance, while warbler finches showed a weaker relationship. Support for the hypothesis that gene flow constrains morphological divergence was only found in one of eight comparisons within these groups. Among warbler finches, genetic divergence was relatively high while phenotypic divergence was low, implicating stabilizing selection rather than constraint due to gene flow. We conclude that the adaptive radiation of Darwin's finches has occurred in the presence of ongoing but low levels of gene flow caused by distance-dependent interisland dispersal. Gene flow does not constrain phenotypic divergence, but may augment genetic variation and facilitate evolution due to natural selection. Both microsatellites and mtDNA agree in that subsets of peripheral populations of two older groups are genetically more similar to other species that underwent dramatic morphological change. The apparent decoupling of morphological and molecular evolution may be accounted for by a modification of Lack's two-stage model of speciation: relative ecological stasis in allopatry followed by secondary contact, ecological interactions and asymmetric phenotypic divergence.

Host Specialization and Geographic Localization of Avian Malaria Parasites: A Regional Analysis in the Lesser Antilles

We recovered 26 genetically distinct avian malaria parasite lineages, based on cytochrome b sequences, from a broad survey of terrestrial avifauna of the Lesser Antilles. Here we describe their distributions across host species within a regional biogeographic context. Most parasite lineages were recovered from a few closely related host species. Specialization on one host species and distribution across many hosts were both rare. Geographic patterns of parasite lineages indicated limited dispersal and frequent local extinction. The central islands of the archipelago share similar parasite lineages and patterns of infection. However, the peripheral islands harbor well-differentiated parasite communities, indicating long periods of isolation. Nonetheless, 20 of 26 parasite lineages were recovered from at least one of three other geographic regions, the Greater Antilles, North America, and South America, suggesting rapid dispersal relative to rate of differentiation. Six parasite lineages were restricted to the Lesser Antilles, primarily to endemic host species. Host differences between populations of the same parasite lineage suggest that host preference may evolve more rapidly than mitochondrial gene sequences. Taken together, distributions of avian malarial parasites reveal evidence of coevolution, host switching, extinction, and periodic recolonization events resulting in ecologically dynamic as well as evolutionarily stable patterns of infection.

The Contribution of ‘Social Capital’ to Economic Growth: Lessons from Island Jurisdictions

This paper is concerned with the relationship of ‘social capital’ to economic development, with a deliberate focus on island territories. It argues that an appreciation of ‘social capital’ theory makes for a more informed understanding of how many (though not all) small, peripheral and network-driven island societies develop ‘good governance’ practices and manage a commendable standard of living. ‘Island neo-corporatism’ merits recognition on its own terms as the deep structure to ‘good governance’; and, in combination with jurisdictional powers, it is a key primer of economic development.

Host Specialization and Geographic Localization of Avian Malaria Parasites: A Regional Analysis in the Lesser Antilles

We recovered 26 genetically distinct avian malaria parasite lineages, based on cytochrome b sequences, from a broad survey of terrestrial avifauna of the Lesser Antilles. Here we describe their distributions across host species within a regional biogeographic context. Most parasite lineages were recovered from a few closely related host species. Specialization on one host species and distribution across many hosts were both rare. Geographic patterns of parasite lineages indicated limited dispersal and frequent local extinction. The central islands of the archipelago share similar parasite lineages and patterns of infection. However, the peripheral islands harbor well‐differentiated parasite communities, indicating long periods of isolation. Nonetheless, 20 of 26 parasite lineages were recovered from at least one of three other geographic regions, the Greater Antilles, North America, and South America, suggesting rapid dispersal relative to rate of differentiation. Six parasite lineages were restricted to the Lesser Antilles, primarily to endemic host species. Host differences between populations of the same parasite lineage suggest that host preference may evolve more rapidly than mitochondrial gene sequences. Taken together, distributions of avian malarial parasites reveal evidence of coevolution, host switching, extinction, and periodic recolonization events resulting in ecologically dynamic as well as evolutionarily stable patterns of infection.

From Harvesting the Sea to Stock Rearing Along the Atlantic Façade of North-West Europe

By 3000 BC, farmers had settled most of the small islands of north-western Europe. This implies the transportation of domestic animals by sea, sometimes over long distances, and the adaptation of herding techniques to new marine environments. While many of the same islands were in use in the Mesolithic period, the nature and extent of this use appears to have been quite different. Zooarchaeological and stable isotopic analysis converge to suggest that the diet of human communities at this time was heavily reliant on marine foods. Neolithic settlements located in the same setting offer a contrasting view. Shell middens were still present at this time, and the remains of fish, marine birds and sea mammals confirm that marine resources were still exploited, but isotopic evidence highlights their minor contribution to the diet. This, combined with the faunal dominance of cattle, sheep and pig, indicates a reliance on domesticated resources. By the end of the Neolithic, even the most peripheral islands of north-western Europe were being exploited primarily for their terrestrial resources. This paper presents evidence from selected sites in western France and Orkney, and then proceeds to offer some possible explanations for the observed patterns of small island use in the Neolithic.

From Harvesting the Sea to Stock Rearing Along the Atlantic Façade of North-West Europe

By 3000 BC, farmers had settled most of the small islands of north-western Europe. This implies the transportation of domestic animals by sea, sometimes over long distances, and the adaptation of herding techniques to new marine environments. While many of the same islands were in use in the Mesolithic period, the nature and extent of this use appears to have been quite different. Zooarchaeological and stable isotopic analysis converge to suggest that the diet of human communities at this time was heavily reliant on marine foods. Neolithic settlements located in the same setting offer a contrasting view. Shell middens were still present at this time, and the remains of fish, marine birds and sea mammals confirm that marine resources were still exploited, but isotopic evidence highlights their minor contribution to the diet. This, combined with the faunal dominance of cattle, sheep and pig, indicates a reliance on domesticated resources. By the end of the Neolithic, even the most peripheral islands of north-western Europe were being exploited primarily for their terrestrial resources. This paper presents evidence from selected sites in western France and Orkney, and then proceeds to offer some possible explanations for the observed patterns of small island use in the Neolithic.

Differential geographic patterns of mitochondrial DNA variation in two sympatric species of Japanese wood mice, Apodemus speciosus and A. argenteus.

We examined the gene sequences of mitochondrial cytochrome b (cyt b) in two Japanese wood mouse species, Apodemus speciosus (n = 89) and A. argenteus (n = 46), which are distributed on the four main islands of Japan (Hokkaido, Honshu, Shikoku, and Kyushu) and on the small islands surrounding them. Apodemus speciosus, the larger of the two species, showed substantial genetic variation, with a maximum of 3% sequence divergence, and remarkable phylogenetic subdivision with two major clades. One clade represents haplotypes from a central region, including Honshu, Shikoku, Kyushu, and their adjacent islands; the other clade includes haplotypes from Hokkaido and the peripheral islands, forming four subclades: a) Hokkaido, b) Sado Island, c) Satsunan Islands, and d) the Izu Islands. Sequence divergence among the four subclades was 1.0 to 1.5%, implying that A. speciosus colonized these geographic regions 0.2 to 0.3 million years ago, assuming a substitution rate of 2.4% per million years. The population on the Izu Islands has preserved haplotypes that are distinct from those in any other region, providing good evidence for the natural colonization of the volcanic islands of the Izu Islands. The cyt b sequence variation had no relation to the karyotypic dimorphism for the eastern (2n = 48) and western (2n = 46) geographic groups, between which a strict border exists at central Honshu. On the other hand, Apodemus argenteus, the smaller of the two species, showed a similar level of sequence divergence (maximum of 3%) but no substantial geographic differentiation: populations in Hokkaido, Sado, and Yakushima shared similar haplotypes with each of the central populations, suggesting that genetic exchanges occurred among the localities in the last 0.15 million years. The apparent genetic structure of the mitochondrial DNA found in the A. speciosus population might be caused solely by long-term existence in insular regions, presumably due to ecological superiority relative to A. argenteus.

Long Transport Chains: Exporting from a Peripheral Island

The crucial dependence on intermodal transport of an open island economy, where almost all external trade passes through the seaports, is examined. The rapid growth of the Irish economy puts great strains on the transport supply chains, particularly in the vicinity of the principal seaport in Dublin, where major congestion occurs. This adversely affects the competitiveness of small and medium-sized exporting companies. Increasing prosperity has resulted in an explosion in the numbers of private cars, which puts great strain on an inadequate internal infrastructure. A review of Irish ports confirms that congestion on the access routes to the Dublin port is the major bottleneck in the long transport chains for exporters. Relief from the freight traffic transiting the city center must await the completion of a dedicated port access tunnel, and interim solutions are needed. In the case of food exporters, globalization, the power of the retail conglomerates, and peripheral location demand a high level of supply chain efficiencies. A survey of export transport chains for selected products shows that transit costs can be a significant proportion of the total consignment value. At the level of the indigenous companies, supply chain management capabilities are shown to be below an acceptable standard in two-thirds of the firms surveyed. Possible solutions for facilitation of freight access in the vicinity of the port and for introduction of more sustainable solutions for goods deliveries in the historic city center are explored. Measures that can be taken to improve the logistics management capabilities in companies are also described.

GROWTH AND OCCUPATIONAL STRUCTURES OF MILLION CITIES OF INDIA

The past few decades have witnessed a rapid mushrooming growth of million cities in India. They now reveal a wide spatial distribution over the country; the exception being the northeastern and hilly states, and the peripheral islands. However, differential growth rates for these cities have become noticeable, and may become more so in the future. The question that comes to mind is: are the rates of growth in any way related to the occupational patterns of these cities? Again, do the growth and occupational structures of the various cities shed any light on the nature of urbanization of India or even the third world as a whole? This is an attempt to investigate the population growth patterns of the million cities of India, and their occupational structures. Secondary data from the Census of India are used in the study. The paper concludes that the younger million cities with a sound industrial base have grown at a much faster rate than the older mega cities. The result has been the lessening of the importance of the four traditional mega cities and their regional economy-driven urbanization. Yet, in general, it appears there is very little relationship between the rate of growth and proportions of employment of the labour force in either the primary, secondary or tertiary sectors. Clearly, the role played by an individual million city in its regional economy seems to be the determining factor of its growth. Finally, it is observed that the historical trajectory of urban growth in countries such as India is quite different from that of the industrialized world.

Ireland’s seaport system

Ireland is the most trade dependent country in the European Union. As a peripheral island economy, an effective seaport system is essential to link into international trade and facilitate export‐led development. During the 1980s, the growth in maritime trade was dispersed to benefit most of Ireland’s ports, although more recently traffic has polarised strongly on the ports of Cork, Dublin, Rosslare, the Shannon Estuary and Waterford. Four processes have played key roles in changing the comparative advantages of Irish ports and stimulating trade: deflection of trade to Northern Ireland ports; Europeanisation and globalisation; industrial policy and economic restructuring; peripherality and transport policy. National Development Plans have used structural funds to reduce the costs of peripherality and have focused investment on four strategic national ports which service two corridors of trade across the Irish Sea. A new context for port management has been created under the 1996 Harbours Act.

Analysis of potential for market penetration of renewable energy technologies in peripheral islands

Cape Verde Islands have important energy and water problems that limit their social and economic development. A field study will be performed focused on Cape Verde Islands to describe the present and future regional power market and to give a clear indication of the best strategies for the optimization of the power energy supply mix in Cape Verde Islands. The study will take into consideration renewable energy technologies and the concerned social, economic and environmental aspects of a given set of possible strategies. One case study will be considered in detail: the situation of the Santo Antão Island. Different energy technologies will be considered: solar, wind, geothermal and biomass. The present structure of the energy sector (capacity, distribution); energy demand, supply and trend; generating plants and infrastructures of Santo Antão will be described.

Patterns of visual field progression in patients with retinitis pigmentosa

Objective The purpose of the study was to determine whether distinct patterns of visual field progression are present in patients with retinitis pigmentosa (RP) and to evaluate the correlation between these patterns, if present, and different genetic subtypes of RP. Design A retrospective analysis of patterns of visual field progression in RP was performed. Participants Visual field of 162 patients with RP, including 55 with type 2 Usher syndrome, who had at least 3 Goldmann visual field examinations during a period of at least 3 years were reviewed. Main outcome measures Goldmann visual fields. Results Visual fields of 86 patients could be classified into one of three specific patterns of visual field progression. Pattern I included those patients with a progressive concentric loss of visual fields; pattern II included those with visual field loss that began superiorly and subsequently developed an arcuate scotoma that progressed either from the nasal (IIA) or the temporal (IIB and IIC) side; and pattern III included patients whose visual field loss was characterized initially by a complete or incomplete midperipheral “ring scotoma” that broke through into the periphery. The end stage of all these patterns was a residual central visual field, sometimes also associated with a small peripheral island. In 53 of the 162 patients, the pattern of visual field loss could not be categorized because of an advanced stage of field loss at the time of the initial examination. Conclusions Distinctive patterns of visual field progression can be observed in patients with retinitis pigmentosa and type 2 Usher syndrome. There were no intrafamilial variations in the pattern of visual field loss in our data on 24 patients from 11 families. Within certain genetic subtypes, there was a predilection for a preponderance of a specific pattern of visual field progression. Future studies may be able to correlate these patterns of visual field loss with different genetic mutations. A greater understanding as to why certain patterns of field loss exist could potentially provide greater insight into the various pathogenetic mechanism(s) by which photoreceptor cells degenerate in this group of patients.

Atomic exchange processes in sputter deposition of Pt on Pt(111)

We have conducted a theoretical study of atomic exchange processes occurring as Pt atoms are deposited on a Pt(111) surface. Using an embedded atom method type interaction potential, we have systematically sampled sites atop a heptamer and at straight A and B type steps to correlate incident atom energy and regions of impact with the probability of ‘push-out’ events, where deposited atoms displace peripheral island atoms. Push-out events lead to incorporation of the incident atom in the growing layer and, thereby, can contribute to layer-by-layer growth if islands are small enough. We find the probability of push-out events to be large for incident energy typical for sputter deposition, 10 and 20 eV. To some extent the 20 eV incident energy also results in detrimental effects, such as displacement of surface atoms (interface mixing), vacancy formation, and displacement of island atoms to positions atop the growing layer, promoting multilayer growth. We have evaluated the minimum energy paths and activation energy barriers for several representative exchange processes observed in the simulations. The calculated activation energy is surprisingly low, typically in the range of 0.6–0.8 eV, even for processes involving displacements of multiple atoms.

Low-temperature homoepitaxial growth of Pt(111) in simulated vapor deposition.

Several atomic processes enhancing layer-by-layer growth have been identified in simulated deposition of Pt atoms onto Pt(111) at 275 K. After depositing the equivalent of one and two monolayers, only ca. 10% of the atoms sit atop the primary growing layer. Impinging atoms accelerate strongly towards the surface and can displace peripheral island atoms. Excess kinetic energy is generated that can effect annealing, even several atoms away from the impact site. Adatoms can descend at island edges only by an exchange diffusion mechanism, particularly at kink sites and vacancy islands.

Latitudinal and insular variation of skull size in crab-eating macaques (primates, Cercopithecidae: Macaca fascicularis).

Macaca fascicularis is broadly distributed in Southeast Asia across 30 degrees of latitude and 35 degrees of longitude (Indochinese Peninsula, Isthmus of Kra, Malay Peninsula, Greater and Lesser Sunda Islands, Philippine Islands, and numerous small, neighboring islands). The range is divisible into 1) a core area comprised of mainland Southeast Asia, Borneo, Sumatra, and Java (large land masses interconnected during the last glacial maximum, 18,000 B.P.); 2) shallow-water fringing islands, which are smaller islands connected to the core area during the last glacial maximum; and 3) deep-water fringing islands, which are peripheral islands not connected to the core area during the last glacial maximum. Skull length was used to study effects of latitude and insularity on patterns of size variation. The data are from 802 adult M. fascicularis specimens from 140 core-area localities, 63 shallow-water islands, and 29 deep-water islands. Sex-specific polynomial regressions of skull length on latitude were used to describe skull length variation in the core area. These regressions served as standards for evaluating variation among samples from shallow-water and deep-water islands. The core area exhibits Bergmannian latitudinal size clines through most of the species range. Thus, skull length decreases from about 8 degrees S (Java) to the equator (Sumatra and Borneo), then increases as far north as about 13 degrees N (Isthmus of Kra). Farther north, to the northernmost Indochinese localities at about 17 degrees N, skull length in M. fascicularis decreases with increasing latitude, contrary to Bergmann's rule. Latitudinal size variation in shallow-water fringing islands generally parallels that in the core area. However, skull length tends to be smaller than in the core area at similar latitudes. Deep-water fringing islands are markedly more variable, with relatively small specimens in the Lesser Sunda Islands and relatively large specimens in the Nicobar Islands. These analyses illustrate how a primate species may vary in response to latitudinal temperature variation and to isolation.

Ecotourism in the small island Caribbean

Ecotourism-related strategies can serve to enhance the tourism industries of small Caribbean islands, which are presently dominated by a 3S (sea, sand, sun) product. In the first place, the principles of Alternative Tourism can be applied to 3S tourism in order to minimize negative environmental impacts. Secondly, diversionary ecotourism opportunities can be promoted to diversify the tourism product, thus providing a nature-oriented alternative to resort-based tourists. Thirdly, regional ecotourism, catering to ecotourists, can be fostered in mountainous interiors, peripheral islands, undeveloped coastlines, rural agricultural areas and in offshore reefs. A fourth strategy, exemplified by Dominica, entails a comprehensive ecotourism approach for destinations in which 3S tourism is undesired or unsuited.

Only thirty minutes from the Great Circle route: Canada's peripheral Atlantic islands

Abstract Canada's Atlantic Provinces contain three major islands, Prince Edward Island, Cape Breton Island and Newfoundland, which suffer from economic and social problems which Canadian regional policy has had some success in alleviating, but the islands still have to cope with their multiple peripherality and resource limitations.

沖縄県八重山群島におけるマラリア流行と人口変動

Influences of epidemic of Falciparum malaria on the population dynamics of communities and families before the introduction of modern medicine for the prevention and treatment of malaria were evaluated in Yaeyama Islands in Okinawa Prefecture. Population growth and structure in a period (1880-1911) in the Meiji era were compared between 4 hamlets each in the highly infected Iriomote Island (M [Main]-Island) and in the non-infected neighboring peripheral islands (P [Peripheral]-Islands). Although malaria was not endemic in P-Islands, the inhabitants of these islands were also exposed to malaria because they temporarily visited M-Island for cultivating rice and collecting forest resources. Changes of population were examined during two successive periods: period I (1880-1903), during which free moving between hamlets was prohibited by the poll tax law; and period 11 (1903-1911), after the abolition of the law. The results are summarized as follows: 1) The prevalence of malaria in all ages of both sexes was prominently higher in M-Island (26.5%) than in P-Islands (3.4%). The difference in prevalence was prominent among children aged 0-9 years: over 70% in M-Island vs. much less in P-Islands. The prevalence among women in the reproductive age was also higher in M-Island than in P-Islands. 2) Both population and number of households in M-Island hamlets slightly decreased (median was -2.7%o/year in population and -1.2%o/year in households) in period I. This decreasing trend was accelerated in period II (-21%o in population and -13 .5%o in households) by emigration. On the other hand, those in P-Islands highly increased throughout both periods (period I, 16%o increase in population and 18%o in households; period II, 11.8%o in population and 4%o in households). The household members in MIsland hamlets was significantly smaller (median was 3.47 in period I and 3.4 in period II) than in P-Islands (4.75 in period I and 5.74 in period II) in both periods. 3) In period I, when migration was restricted, the ratios of number of children aged under 15 years and of older persons over 50 to the adults aged 15-49 were significantly smaller in M-Island than in P-Islands. 4) The vital statistics in period I were estimated by the West type's stable population model. Crude and infant death rates were significantly higher in M-Island than in PIslands. Life expectancy was also significantly shorter in M-Island. No statistically significant difference in crude birth rate was found between M-Island and P-Islands presumably of a larger variation among the hamlets in M-Island than in P-Islands. 5) These results suggest that the population decrease in M-Island in period I was caused by the high death rate in particular among children due to malaria and related complications. In P-Islands, it is inferred that malaria was only prevalent among men of working age, who engaged in inter-insular cultivation. The low death rate among children and high birth rate in P-Islands are attributable to this communal preventive behavior system against malaria. This probably contributed to the high population growth rate. For the malaria control measures of the day, further efforts should be paid to the evaluation of preventive behavior system focused on children and mothers.

Floristic Composition and Community Structure in an Area of Cerrado in SE Brazil

Summary Cerrado is the generic name for the savanna-like vegetation which occupies the vast area of the central Brazilian plateau and also extends into peripheral, fragmented islands within the Surrounding moist forests. Cerrado occurs as a complex of intergrading structural sub-types which range from more or less closed forest to open grassland with scattercd shrubs, and it also shows phytogeographical shifts in floristic composition although these are as yet poorly studied. This investigation presents for the first time a full list of the woody species from one of the peripheral islands of cerrado in Sao Paulo state. In addition, a principal components analysis of the data from 60 quadrats of 10 × 25 m indicates that the two community subtypes present in this area, cerrado and campo cerrado, distinguished by Goodland on the basis of physiognomic characteristics, can also be defined in terms of species composition. The possible causes for these floristic and physiognomic sub-communities are examined but no single controlling factor can be established.